Various work on Actions...
Adding new PossibleAction, new ParamUtil methods...

Game.java
    - finished initializing Players
PossibleAction.java
    - Added javadoc
PossibleRefutal.java
    - Created and implemented (more work required)
Player.java
    - Replaced Card for Item, added more Constructor parameter checks
      (ParamUtil)
ParamUtil.java
    - Added checks for blank strings, empty collections.